Question: Solve for $r$: \[\frac{r-45}{2} = \frac{3-2r}{5}.\]
Explanation: Multiplying both sides by 2 and by 5 to eliminate the fractions gives \[5(r-45) = 2(3-2r).\] Expanding both sides gives $5r - 225 = 6-4r$.  Adding $4r$ and 225 to both sides gives $9r = 231$, so $r = \frac{231}{9} = \boxed{\frac{77}{3}}$.